What exactly is B9 two family miscellaneous?

I'm trying to understand this code as clearly as possible, but NYC legal resources can be archaic. In short, I'm trying to break my lease which has 7 months left and have offered a total of 3.5 months notice including security and an additional month's notice, but the landlord in unwilling to negotiate AT ALL. This B9 two family miscellaneous brownstone currently houses 3 units. The unit I'm in (garden) may be illegal. Oddly enough, my lease reads 'third floor' when I'm on the garden level and my landlord photographs and emails me the Con-ed bill. I have heard that if this is an 'illegal three' as they are known, the housing court would not hear the case and she therefore could not sue me. It's not the route I prefer to go down, but.. Can anyone shed light on this? Really